ST ELEVATION Jason Mitchell, PGY2 July 15, 2010

Context CP and ST Elevation common ED presentation Correct ECG interpretation impacts management decisions and patient outcome Certain patients with CP and ST elevation require rapid intervention via thombolysis or PCI Misdiagnosis potentially harmful

Context 1996 ACC/AHA Class I Recommendation for Thrombolysis “ST elevation greater than 0.1 mV in two or more contiguous leads.”1 1 Ryan TJ, Anderson JL, Antman EM, et al. ACC/AHA guidelines for the management of patients with acute myocardial infarction. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Management of Acute Myocardial Infarction). .J Am Coll Cardiol. 1996 Nov 1;28(5):1328-428

Context Disorders with ST Elevation Meeting ACC/AHA Thrombolysis Guideline Acute Myocardial Infarction Early Repolarization Left Ventricular Hypertrophy Left Ventricular Aneurysm Left Bundle Branch Block Ventricular Paced Rhythm Hypothermia (Osborn Waves) Hyperkalemia Brugada Syndrome Pulmonary Embolism Acute Cerebral Hemorrhage WPW

Context 2000 ACEP Qualifier “ST-segment elevations greater than 0.1 mV in 2 or more contiguous leads that are not characteristic of early repolarization or pericarditis, nor of a repolarization abnormality from LVH or BBB in patients with clinical presentation suggestive of AMI.”2 2 Critical issues in the evaluation and management of adult patients presenting with suspected acute myocardial infarction or unstable angina. Ann Emerg Med 2000;35:521-525

ST Morphology

ST Morphology Concave Up vs. Concave Down

ST Morphology Concave Up vs. Concave Down

ST Segment Elevation Differentiating STEMI from other ST Elevation Syndromes Dynamic ECG changes Reciprocal Changes

ST Morphology

STEMI Territories Localizations

STEMI

STEMI

STEMI

Responsible Vessel(s) STEMI Location Leads Responsible Vessel(s) Reciprocal Change Anterior V1 – V4 Septal: V1 – V2 LAD II, III, aVF Lateral I, aVL, V5, V6 RCA Circumflex III, aVF, V1 Inferior RCA (80%) Circumflex (15%) Both (5%) aVL, I Posterior V1 – V3 (Depression)

Context 2000 ACEP Qualifier “ST-segment elevations greater than 0.1 mV in 2 or more contiguous leads that are not characteristic of early repolarization or pericarditis, nor of a repolarization abnormality from LVH or BBB in patients with clinical presentation suggestive of AMI.”2 2 Critical issues in the evaluation and management of adult patients presenting with suspected acute myocardial infarction or unstable angina. Ann Emerg Med 2000;35:521-525

Early Repolarization

Early Repolarization Normal variant Males > Females ECG Findings: Diffuse, Concave up ST Elevation 2-5mm (Usually precordial) Notched J-Point Prominent T-Waves Temporal stability

Early Repolarization “Benign” Early Repolarization Increased prevalence of early repolarization in idiopathic VF Most pronounced with inferior J-Point elevation Increased risk of cardiac death (ie – sudden arrythmia) J-Point 1mm: RR 1.28, 95% CI 1.05 – 1.59 J-Point 2mm: RR 2.98, 95% CI 1.85 – 4.923 Isolated BER in limbs leads should prompt ACS investigations 3 Tikkanen JT, Anttonen O, Junttila MJ, et al. Long-term outcome associated with early repolarization on electrocardiography. N Engl J Med. 2009 Dec 24;361(26):2529-37.

Pericarditis

Pericarditis Diffuse ST Elevation Diffuse PR Depression Caveat: aVR ST Depression, PR Elevation

Pericarditis Stages – All 4 Present in ~50% of patients I – ST Elevation, concordant T-Waves, PR Depression II – ST segments return to baseline, T-Waves flatten III – T-Wave inversion IV – T-Wave resolution

Pericarditis Differentiation from STEMI Concave Up ST segments ST elevation beyond contiguous leads No simultaneous T-Wave inversion Reciprocal changes absent Serial ECGs not consistent with STEMI patterns No Q-Wave development

Pericarditis vs. BER Differentiation of Pericarditis from BER V6 ST/T Ratio Pericarditis > 0.25 BER < 0.25

LVH

LVH Tall R waves lateral leads Deep S waves anterior precordial leads Concave Up ST elevation, typically V1-V3 LAD

LBBB

LBBB Wide QRS Large, positive R wave without q or s waves in I, aVL, V6 Notched ‘M Shaped’ R wave V5, V6 Normal or leftward axis ST depression and T wave inversion in leftward leads ST elevation and upright T waves in right precordial leads

LBBB 7% of MI4 Significantly less likely to receive ASA Increased in-hospital mortality 4 Go AS, Barron HV, Rundle AC, et al. Bundle-branch block and in-hospital mortality in acute myocardial infarction. National Registry of Myocardial Infarction. Ann Intern Med 1998 Nov 1;129(9):690-7.

LBBB Sgarbossa Criteria5 Score ≥ 3 98% specific 20% sensitive6 Criterion Score Concordant ST Elevation ≥ 1mm, any lead 5 ST Depression ≥ 1mm, V1-V3 3 Discordant ST Elevation ≥ 5mm, any lead 2 5 Sgarbossa EB, Pinski SL, Barbagelata A, et al. Electrocardiographic diagnosis of evolving acute myocardial infarction in the presence of left bundle-branch block. GUSTO-1 (Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries) Investigators. N Engl J Med 1996 Feb 22;334(8):481-7. 6 Tabas JA, Rodriguez RM, Seligman HK, et al. Electrocardiographic criteria for detecting acute myocardial infarction in patients with left bundle branch block: a meta-analysis. Ann Emerg Med. 2008 Oct;52(4):329-336.e1.

LBBB

LBBB ECG Evolution Anterolateral MI Anteroseptal MI New S Waves in Leftward Leads I, aVL, V6 Anteroseptal MI Lateral q waves I, aVL, V5-V6

RBBB? Can present with ST elevation No impact on initial QRS vector Q waves are not changed

Conclusion Evaluate ECG in relation to clinical presentation ST morphology Dynamic ECG changes, serial ECGs Look for reciprocal changes

Practice

Practice Inferior MI V1 Elevation: RV Infarct ST Elevation III > ST Elevation II: RCA Occlusion

Practice

Practice Hyperacute Anterior MI Note Mobitz II Conduction Block Malfunctioning His-Pukinje system Suggests anterior occlusion Ie - LAD occlusion Mobitz I Conduction Block Malfunctioning AV node Suggests ‘dominant’ coronary occlusion RCA or Circumflex

Practice

Practice Posterior MI Note ‘q’ waves in anterior leads

Practice

Practice WPW

Practice

Practice LBBB Concerning for MI

Practice

Practice Anterior MI